Television broadcast professionals often require the ability to extend one or two channels of voice intercom systems over a long distance. This functionality is required so that certain key production personnel at a remote location can communicate with the rest of the production team on site reliably, clearly, and with full access to the intercom system's functions, including those functions over and above the simple bi-directional transmission of voice communications. Specific television broadcast applications include “outside broadcast” such as sporting, entertainment, or event production, terrestrial (ENG) and satellite (SNG) news gathering, corporate events, and industrial testing environments.
These voice communications may be transmitted and received according to a “two-wire” or “four-wire” format. The two-wire format allows users connected to a communication line to communicate with other users connected to the communication line at any given time. Four-wire communication allows users connected to a communication line to selectively communicate privately with other specific users on a one on one basis. The four-wire formats may include a connection matrix that allows any user connected to the matrix to communicate privately with any other user connected to the matrix. Accordingly, two-wire and four-wire communication lines can operate under separate communication formats and typically require separate hardware units and/or communication lines.